Introduction to Precautions and Workflow of Ultra Clean Workbench

A super clean workbench is a facility that provides a sterile operating environment for laboratory work, to protect experiments from external environmental influences, and to provide some degree of protection for the external environment to prevent contamination and protect operators. Compared with simple sterile hoods, the ultra clean table has the advantages of allowing operators to move freely, easily reaching any part of the operating area, and higher integrity.

（1） Before using the ultra clean workbench, it should be illuminated with ultraviolet light for 30-40 minutes, and check that all openable doors and windows around the operating area are in their working positions. The operation is carried out in the center position of the operation area, which is a relatively safe area in terms of design. Before operating, one should have a preliminary understanding of the experimental materials and also be aware of the performance and safety level of the equipment being used. Strictly implement laboratory safety regulations. The use of specific pathogens in any ultra clean workstation must undergo safety assessment. If the experimental materials cause environmental pollution to the surrounding environment, they should be avoided from use in models without exhaust filter plates, as operating in flowing air is no different from dispersing toxins. Any advanced equipment cannot guarantee the success of experiments. The use of ultra clean workbenches in animal quarantine laboratories is aimed at sterility and avoiding cross contamination.

（2） Maintaining an ultra clean workbench is a relatively precise electrical equipment, and regular maintenance and upkeep are very important. Firstly, it is necessary to maintain dryness and cleanliness indoors. Moist air not only rusts manufacturing materials, but also affects the normal operation of electrical circuits. Moist air is also conducive to the growth of bacteria and mold. A clean environment can also extend the service life of the filter plate. In addition, regular cleaning of equipment is an important part of normal use. Cleaning should include routine cleaning and regular handling before and after use. When fumigating, all gaps should be sealed. For example, for ultra clean workbenches with movable baffle covers at the operating port, plastic film can be used for sealing. The filter plate and UV sterilization lamp of the ultra clean workbench have a calibrated service life and should be replaced on schedule.

（3） The clean environment of the principle ultra clean workbench is formed by the flow of clean air (filtered air) in a specific space according to a set direction. According to the direction of airflow, existing ultra clean workbenches can be divided into vertical, inward outward, and lateral types. Considering the quality of operation and the impact on the environment, a vertical comparison is made. The clean air provided by the gas supply filter plate descends through the operating area at a specific speed, separates in the middle of the operating area, and is sucked away by the front air suction hole and the rear suction window. The air sucked in from the front and rear parts of the operating area is mixed together and pumped into the rear positive pressure area by the blower. In the upper part of the machine, 30% of the gas is discharged from the top through the exhaust filter plate, and about 70% of the gas enters the operating area again through the oxygen supply filter plate. To supplement the air discharged from the exhaust port, the same volume of air is replenished from the room air through the operating port. These air barriers will not enter the operating area, but only form an air barrier.

（4） The ultra clean workbench where debugging is located undergoes strict testing before leaving the factory to ensure normal use. But this does not mean that the manufacturer's testing can replace the operator's necessary inspection and debugging before use. Due to the different environments in which ultra clean workbenches are located, only through appropriate inspection and debugging can the equipment be maximally utilized. Before debugging, a better environment should be selected for the machine. It is recommended to place it in a sterile room with air disinfection facilities. If conditions are not available, the machine should be placed in a room with less human movement and relatively clean conditions. Adjust the height of each foot to ensure stability and the level of the operating surface. The power supply of the ultra clean workbench should use a dedicated circuit to avoid changes in air flow rate caused by circuit overload. Compared to simple sterile hoods, the ultra clean bench has the standard configuration of allowing operators to move freely, easily reaching any part of the operating area, and equipped with ultraviolet sterilization lamps and fluorescent lamps for lighting. The blower provides the power for air flow, and it is clear whether these components are working properly. The difficulty is also important in checking the air filter plate and its sealing, which is directly related to the normal use of the machine. The simple inspection method is the nutrient agar plate method. Newly purchased and unused ultra clean workbenches can be fumigated with UV lamps and other light sources. Then, when the machine is in operation, an open nutrient agar plate should be placed at each corner and center of the operating area. After two hours, the plate should be covered and incubated in a 37 ℃ incubator for 24 hours to calculate the bacterial count. The average number of bacterial colonies per petri dish must be less than 0.5.